MRI machines use a superconducting electromagnet that once energized will run forever. The only power it needs is to maintain the low temps for the superconductor.
The "OFF" switch vents the coolant (helium) outside the hospital so the electromagnet stops superconducting and can turn off.
The "OFF" switch vents the coolant (helium) outside the hospital so the electromagnet stops superconducting and can turn off.
Outside the hospital it would look something like: https://www.youtube.com/shorts/krMbFT0Ums0